DOI: 10.1175/JCLI-D-11-00474.1
Scopus记录号: 2-s2.0-84867677752
论文题名: Seasonal zonal asymmetries in the southern annular mode and their impact on regional temperature anomalies
作者: Fogt R.L. ; Jones J.M. ; Renwick J.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2012
卷: 25, 期: 18 起始页码: 6253
结束页码: 6270
语种: 英语
Scopus关键词: Annular mode
; Antarctic oscillation
; Antarctica
; Climate variability
; ENSO
; Climate control
; Mathematical models
; Climatology
; Antarctic Oscillation
; climate effect
; climate variation
; El Nino-Southern Oscillation
; regional climate
; seasonal variation
; Southern Hemisphere
; temperature anomaly
; zonal flow
; Antarctica
英文摘要: The Southern Hemisphere annular mode (SAM) is the dominant mode of climate variability in the extratropical Southern Hemisphere. Representing variations in pressure and the corresponding changes to the circumpolar zonal flow, it is typically thought of as an "annular" or ringlike structure. However, on seasonal time scales the zonal symmetry observed in the SAM in monthly or annual mean data is much less marked. This study further examines the seasonal changes in the SAM structure and explores temperature signals across the Southern Hemisphere that are strongly tied to the asymmetric SAM structure. The SAM asymmetries are most marked in the Pacific sector and in austral winter and spring, related to changes in the jet entrance and exit regions poleward of 308S. Depending on the season, the asymmetric SAM structure explains over 25%of the variance in the overall SAM structure and has strong connections with ENSO or zonal wavenumber 3. In austral summer and autumn the SAM has been becoming more zonally symmetric, especially after 1980, perhaps tied to changes in anthropogenic forcing. Across the Pacific sector, including the Antarctic Peninsula, temperature variations are strongly tied to the asymmetric SAM structure, while temperatures across East Antarctica are more strongly tied to the zonally symmetric SAM structure. The results suggest that studies examining the climate impacts of the SAMacross the Southern Hemisphere need to consider the seasonal variations in the SAM structure as well as varying impacts between its positive and negative polarity to adequately describe the underlying relationships. © 2012 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52257
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geography, Ohio University, Athens, OH, United States; Department of Geography, University of Sheffield, Sheffield, United Kingdom; National Institute of Water and Atmospheric Research, Wellington, New Zealand
Recommended Citation:
Fogt R.L.,Jones J.M.,Renwick J.. Seasonal zonal asymmetries in the southern annular mode and their impact on regional temperature anomalies[J]. Journal of Climate,2012-01-01,25(18)